DE102017201247A1 - State estimator, energy storage module, vehicle, and state estimation method - Google Patents

Abstract

A state estimator includes: a voltage detection unit that detects voltages of energy storage devices; and an estimation unit that estimates a charge amount difference between at least two of the energy storage devices. At a reference time T0 during a constant current charge, the estimation unit executes: a target voltage setting at the reference time T0 for setting a voltage of a low-voltage energy storage device as the target voltage V0; a time determination for determining a time point at which a voltage of a high-voltage energy storage device reaches the target voltage V0; and a charge amount difference estimation for estimating the charge amount difference between the at least two energy storage devices based on the reference time T0, the time determined in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge.

Description

TERRITORY

The technique disclosed herein relates to a state estimator, an energy storage module, a vehicle, and a state estimation method.

BACKGROUND

In a composite battery having a plurality of energy storage devices connected in series, the amounts of charge of the energy storage device (a charge amount difference may be caused to vary) often vary due to differences in the initial capacities and differences in the degree of aging between the energy storage devices. When a difference in the amount of charge is generated between the energy storage devices, an overvoltage occurs during charging in an energy storage device whose charge amount is relatively large. Therefore, conventionally, a technique for equalizing the charge states is known by estimating a difference in the amount of charge between energy storage devices and discharging (or charging) each of the energy storages based on the charge amount difference ( JP 2011-41452 A ). JP 2011-41452 A discloses a method of determining times at which voltages of the respective energy storage devices reach a given voltage and estimating the charge amount differences based on differences between the times.

However, according to the method of JP 2011-41452 A set the given tension to any static value. This results in a problem that a voltage of an energy storage device often does not reach the given voltage, depending on the target value for the given voltage, and a charge-level difference of the energy storage devices can not be estimated.

OVERVIEW

The present disclosure provides a technique capable of more reliably estimating a difference in the charge amount difference of energy storage devices.

According to one aspect of the present invention, there is provided a state estimator that estimates a state of a plurality of energy storage devices, the state estimation device including: a voltage detection unit configured to detect voltages of the respective energy storage devices; and an estimation unit configured to estimate a charge amount difference between charge states between at least two of the energy storage devices, at a reference time T0 during a constant current charge of the plurality of energy storage devices when one of the two energy storage devices whose voltage is relatively low, as an energy storage device is assumed to be low voltage, and the other of the two energy storage devices whose voltage is relatively high is regarded as a high-voltage energy storage device executing the estimating unit: a target voltage setting process for setting, as a target voltage V0, a voltage of the energy storage device low voltage detected by the voltage detection unit at the reference time T0; a time determination process for detecting a timing at which a voltage of the high-voltage energy storage device reaches the target voltage V0; and a charge amount difference estimation process for estimating the charge amount difference between the at least two energy storage devices based on the reference time T0, the time detected in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge.

According to this structure, it is possible to reliably estimate a difference in the amount of charge and the state of charge of energy storage devices.

BRIEF DESCRIPTION OF DRAWINGS

1 shows a block diagram illustrating a charging system.

2 shows a circuit diagram of a discharge circuit.

3 FIG. 12 is a graph showing a characteristic of the SOC-OCV correlation of secondary batteries. FIG.

4 FIG. 10 is a flowchart showing a process for controlling the alignment. FIG.

5 FIG. 12 is a graph showing a time change of voltage values of the secondary batteries at a final phase of the constant current charge. FIG.

6 FIG. 12 is a flowchart showing a procedure for compensation control according to a second embodiment. FIG.

7 FIG. 12 is a graph showing a time change of voltage values of the secondary batteries during a final phase of the constant current charge according to the second embodiment. FIG.

8th shows a view illustrating an automobile according to a third embodiment.

9 FIG. 12 is a block diagram illustrating a battery module according to the third embodiment. FIG.

10 shows a perspective view illustrating the battery module.

11 shows an elevational perspective view illustrating the battery module.

DESCRIPTION OF EMBODIMENTS

(Overview of embodiments)

First, an outline of the technique disclosed in the embodiments will be given.

The state estimator disclosed herein is a state estimator that estimates a state of a plurality of energy storage devices, the state estimation device including: a voltage detection unit configured to detect voltages of the energy storage devices, respectively; and an estimation unit configured to estimate a charge amount difference between at least two of the energy storage devices, wherein a reference time T0 during a constant current charge of the plurality of energy storage devices in case one of the two energy storage devices whose voltage is relatively small is considered as a low voltage energy storage device , and the other of the two energy storage devices whose voltage is relatively high, is assumed as a high-voltage energy storage device, the estimating unit executes: a target voltage setting process for setting a voltage of the low-voltage energy storage device as a target voltage V0 is detected by the voltage detection unit at the reference time T0; a time determination process for determining a timing at which a voltage of the high-voltage storage direction reaches the target voltage V0; and a charge amount difference estimation process of estimating the difference in the amount of charge between the at least two energy storage devices based on the reference time T0, the time determined during the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge.

By setting a voltage of the one of the two energy storage devices whose voltage is low, as a target voltage, it is possible to reliably determine the time at which the target voltage is reached, since the voltage of the other energy storage device (a Energy storage device whose voltage is relatively high) has already reached the target voltage. With this, it is possible to calculate the time difference between times for reaching the target voltage for the two energy storage devices and to reliably estimate the difference of the state of charge or charge amounts based on the time difference. In this case, during the constant-current charging, the reference time T0 includes a time at the end of the constant-current charge. Meanwhile, during the constant-voltage charging, the current flowing through the energy storage device continuously changes. Therefore, the energy storage devices may have different current values at the time when the target voltage is reached, and their charge states when their voltages have reached the target voltage are hardly considered equal. Therefore, in the case of a constant-voltage charge, it is difficult to estimate the differences in the amount of charge based on the time differences between the times when the voltages of the energy storage devices reach the target voltage. On the other hand, in the case of the contact current charge, when the voltages of the energy storage devices reach the target voltage, the current values are equal, their charge states when their voltages have reached the target voltage are considered equal. Therefore, by multiplying the time differences between the times when the voltages of the energy storage devices reach the target voltage and the current value of the constant current charge, it is possible to estimate the charge amount difference between the energy storage devices. In particular, the technique disclosed herein may be applied when a constant current charge is performed.

Further, the state estimator disclosed herein may be configured such that the plurality of energy storage devices include three or more energy storage devices, and when one of the plurality of energy storage devices whose voltage is lowest at the reference time T0 is regarded as the lowest voltage energy storage device, the estimating unit: in the target voltage setting process, sets a voltage of the lowest-voltage energy storage device as the target voltage V0; determining, in the time-determining process, times at which voltages of the plurality of energy storage devices that are not the lowest-voltage energy storage device reach the target voltage V0; and in the charge amount difference estimation process estimating the landing amount differences between the plurality of energy storage devices based on the reference time T0, the times detected in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge. By setting the voltage of that energy storage device whose voltage is lowest at the reference time T0 as the target voltage, it is possible to reliably determine the timings at which the voltages of the plurality of energy storage devices reach the target voltage.

Further, the state estimating means disclosed herein may be arranged such that the estimating unit: executes a time difference calculating process for calculating time differences between the reference time T0 and the times obtained in the time determining process; and in the charge amount difference estimation process, estimates the differences in the amount of charge between the lowest voltage energy storage device and the energy storage devices that are not the lowest voltage energy storage device based on the time differences calculated in the time difference calculation process. With such a construction, it is possible to estimate the charge amount differences between the energy storage devices based on the lowest voltage energy storage device.

Further, the state estimator disclosed herein may be configured such that the plurality of energy storage devices include three or more energy storage devices, and when one of the plurality of energy storage devices whose voltage is highest at the reference time T0 is adopted as the highest voltage energy storage device, the estimation unit: in the target voltage setting operation sets voltages of the plurality of energy storage devices that are not the highest voltage energy storage device as target voltages V0; in the time determination process, determine timings at which a voltage of the highest-voltage energy storage device reaches the target voltages V0 set in the target voltage setting process; and in the charge amount difference estimation process, estimating the charge amount differences between the plurality of energy storage devices based on the reference time T0, the times detected in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge.

In order to determine the times at which the voltages of the energy storage devices reach the target voltage V0, it is necessary to record the temporal change of the voltages of the energy storage devices. According to the foregoing construction, it is necessary to detect only the temporal change of the voltage of the energy storage device whose voltage is highest, and therefore it is possible to reduce the amount of data to be recorded.

Further, the state estimation means disclosed herein may be arranged such that, when one of the plurality of energy storage devices whose voltage is lowest at the reference time T0 is adopted as a lowest voltage energy storage device, the estimation unit: a time difference calculation process for calculating a time difference between a time T1 and the reference time T0 and time differences between the time T1 and the time points other than the time T1 detected in the time-determining process, wherein the time T1 is a time at which a voltage of the highest-voltage energy storage device executes the time Reaches target voltage V0 of the energy storage device with the lowest voltage; and in the charge amount difference estimation process, estimating the charge amount differences between the lowest voltage energy storage device and the energy storage device from the plurality of energy storage devices that are not the lowest voltage energy storage device based on the time differences calculated in the time difference calculation process. With such a construction, it is possible to estimate the charge amount differences between the energy storage devices based on the lowest voltage energy storage device.

An energy storage module disclosed herein comprises: the plurality of energy storage devices; and the state estimator described above.

A vehicle disclosed herein comprises: the energy storage module as described above; and a vehicle user to which power is supplied from the energy storage module.

A state estimation method disclosed herein is a state estimation method for estimating a state of multiple energy storage devices, the method comprising: at a reference time T0 during a constant current charge from the plurality of energy storage devices, setting a voltage of a low voltage energy storage device as a target voltage V0 wherein one of the at least two of the plurality of energy storage devices is the low-voltage energy storage device whose voltage is relatively low, and the other of the two energy storage devices is a high-voltage energy storage device whose voltage is relatively high; Determining a time at which a voltage of the high-voltage energy storage device reaches the target voltage V0; and estimating a charge amount difference between the at least two energy storage devices based on the reference time T0, the time detected in the time determination, and a current flowing through the plurality of energy storage devices during the constant current charge.

For example, the technique disclosed herein may be applied to a computer program for estimating a condition of multiple energy storage devices.

<First Embodiment>

With reference to 1 to 5 A first embodiment is described in which the technique disclosed herein relates to a charging system 10 is applied.

1. Structure of the charging system 10

As in 1 is shown, the charging system 10 a composite battery 30 , a battery management device 50 (hereinafter referred to as BM), which is the merged battery 30 controls, and a battery charger (power generator) 11 for charging the assembled battery 30 on.

The assembled battery 30 has several secondary batteries 31 which are connected in series. As in 1 is shown, the BM 50 a controller 60 , a discharge circuit 70 , a voltage detection circuit 80 , a current sensor 40 and a temperature sensor 95 on. The discharge circuit 70 is for each of the secondary batteries 31 intended. As in 2 is shown, the discharge circuit 70 a discharge resistor R and a discharge switch SW and is in parallel with the secondary batteries 31 connected. By supplying a command from the controller 60 for turning on the discharge switch SW, the secondary batteries 31 be discharged separately.

As in 1 is shown is the voltage detection circuit 80 via a detection line with both ends of the secondary batteries 31 connected and serves to measure a voltage of each of the secondary batteries 31 in response to a command from the controller 60 , The temperature sensor 95 is a contact sensor or a non-contact sensor and serves to measure the temperature of the secondary batteries 31 , Here are the secondary batteries 31 an example of "energy storage devices" and the BM 50 is an example of a "state estimator". Further, the voltage detection circuit 80 an example of a "voltage detection unit".

The current sensor 40 is used to detect a current passing through the secondary batteries 31 flows. The current sensor 40 is designed so that it has current values of the secondary batteries 31 with constant frequency and data for the measured current value to the controller 60 transmitted. The secondary batteries 31 and the current sensor 40 are over a wiring 35 connected in series and with the battery charger 11 connected.

The control 60 has a central processing unit (hereinafter referred to as a CPU) 61 , a store 63 and a timer unit 64 on. The control 60 serves to control the discharge circuit 70 to the charge quantities of all secondary batteries 31 compensate. The term "equalization" herein denotes a case of equalizing the charge amounts of the secondary batteries 31 and the case of reducing a difference between the charge amounts of the secondary batteries 31 , Here is the controller 60 an example of a "guessing unit".

The memory 63 includes a computer program for performing an operation for balancing amounts of charge of the secondary batteries 31 ("Sequence for Performing Compensation Control" described later) and the like. The timer unit 64 Used for time monitoring of the assembled battery 30 while loading. In addition to the components described above, the charging system 10 an operation unit (not shown) for receiving an input from an operator and a display unit (not shown) for displaying states and the like of all the secondary batteries 31 on.

Every secondary battery 31 For example, an iron-phosphate-based lithium-ion secondary battery containing lithium-iron-phosphate (LiFePO 4) as a positive active material and graphite as a contains negative active material. 3 shows the characteristic of SOC-OCV correlation of the secondary battery 31 , As in 3 is shown, contains the secondary battery 31 a small change area in which a change amount of the OCV relative to a change amount of the SOC is relatively small, and a large change area in which a change amount of the OCV relative to a change amount of the SOC is relatively large.

In particular, as in 3 is shown, the secondary battery 31 an area in which the OCV (idle running voltage) increases rapidly in relation to a rise of the SOC (high-change area) in an early stage of charging (a final stage of discharging) in which the SOC is lower than 10%, and in FIG a final stage of loading in which the SOC is 90% or higher. Furthermore, the secondary battery includes 31 a region in which the OCV is substantially constant with respect to the rise of the SOC (area of small change, plateau area) in a middle stage of charging (a middle stage of discharge), the SOC being 10% or higher and smaller than 90% is.

If there is a difference in the amount of charge (a difference in the remaining capacity) in the multiple secondary batteries 31 There are such a characteristic that an overvoltage occurs in the final stage of charging in one of the secondary batteries 31 whose charge amount is relatively large, and this may cause aging or damage. Therefore, the compensation control for the assembled battery 30 frequently used, for example, before delivery.

When doing the composite battery 30 is charged using a facility that is capable of voltages of the secondary batteries 31 It is possible to control the occurrence of an overvoltage in a special battery of the secondary batteries 31 to avoid. However, the composite battery becomes 30 often used without the use of such a system. By balancing the charge quantities of the secondary batteries 31 It is possible to detect the occurrence of overvoltage in the secondary batteries 31 to avoid, even if a plant, the voltages of the secondary batteries 31 can control separately, is not provided.

2. Sequence for the execution of the compensation control

Next, a sequence for performing a compensation control for the assembled battery will be described 30 described. The sequence for executing the equalization control, which in 4 2, steps S10 to S90 are included. In particular, in this embodiment, a charge amount difference of the secondary batteries 31 estimated after a constant current charge on the assembled battery 30 is made, and a compensation operation is performed on the basis of the charge amount difference. In doing so, the equalization control on the assembled battery 30 for example, performed before delivery, but the time at which the compensation control is executed is not limited to the time before delivery. Furthermore, the following describes an example in which the composite battery 30 four secondary batteries 31 having.

<Operation during the constant current charge>

If, as in 4 is shown, for example, the composite battery 30 with the battery charger 11 is connected by an operator and a constant current charge of the assembled battery 30 via the battery charger 11 starts (S10), then draws the CPU 61 Voltage values of the secondary batteries 31 in the store 63 on (S20). In particular, the CPU draws 61 that from the timer unit 64 predetermined time (for example, a time based on a time when the constant-current charge starts) and records the voltage values of the secondary batteries 31 allocated at this time in the memory 63 on. Then after completion of the constant current charge of the assembled battery 30 by means of the battery charger 11 (S30) terminates the CPU 61 the recording of the voltage values of the secondary batteries 31 (S40).

In steps S50 to S80, a process for estimating the charge amount difference of the plurality of secondary batteries becomes 31 (State estimation method) based on the voltage values recorded in S40. Steps S50 to S80 will be referred to an example of a time change of the voltage values of the four secondary batteries 31 described (see 5 ). 5 shows a graph showing the change over time of the voltage values of the secondary batteries 31 in the final phase of the constant current charge shows. Here are the in 5 The values shown are examples only and are not limitative for this embodiment. Further shows 5 the four secondary batteries 31 such that they have different voltage values (and thus charge quantities or states of charge). In the following description, the four secondary batteries 31 by reference numerals 31A - 31D in descending order correspond to the voltage denoted.

<Zielspannungseinstellvorgang>

Next comes the CPU 61 as a target voltage V0, a voltage of those secondary battery 31D one whose voltage is lowest at a time (for example, 3.529 V in 5 ) at which the constant current charge ends (hereinafter referred to as the reference time T0 (see 5 ) (S50). Here is the secondary battery 31D an example of a "lowest voltage energy storage device" and a "low voltage energy storage device". Further, each of the secondary batteries 31A - 31C an example of a "high voltage energy storage device". Further, the reference timing T0 is an example of the "reference timing during the constant current charge". In this embodiment, a state for terminating the charging is, but not limited to, a voltage of the secondary battery 31A whose voltage is highest and reaches 3.61V.

<Time determination process>

Next, the CPU determines 61 corresponding to times T1-T3 at which voltages of the secondary batteries 31A - 31C that is not the secondary battery 31D are, the target voltage V0 reach (S60).

<Time difference calculation process>

Next, the CPU calculates 61 time differences DT1 - DT3, respectively, between the reference time T0 and the times T1-T3 obtained in the time-determining process (S70). The time differences DT1 - DT3 are calculated based on the following expressions (1) to (3). Time difference DT1 = time T0 - time T1 (1) Time difference DT2 = time T0 - time T2 (2) Time difference DT3 = time T0 - time T3 (3)

<Ladungsmengendifferenzabschätzvorgang>

Next, the CPU estimates 61 the charge amount differences between the secondary battery 31D and the respective secondary batteries 31A - 31C based on the time differences DT1 - DT3 from (S80). The charge amount differences can each be obtained by multiplying the time difference by the charge current. In particular, when the charge amount difference between the secondary battery 31D and the secondary battery 31A DC1 is the charge amount difference between the secondary battery 31D and the secondary battery 31B is equal to DC2 and if the charge quantity difference between the secondary battery 31D and the secondary battery 31C is equal to DC3, then the charge amount differences DC1 - DC3 are calculated based on the following expressions (4) to (6), respectively. Charge quantity difference DC1 = time difference DT1 · charge current ZI (4) Charge quantity difference DC2 = time difference DT2 · charging current ZI (5) Charge quantity difference DC3 = time difference DT3 · charge current ZI (6)

In the foregoing expressions (4) to (6), the charging current ZI is a current passing through the assembled battery 30 flows during the constant current charging and, for example, by the current sensor 40 is measured.

<Settlement process>

Next, the CPU is the same 61 the charge quantities of the secondary batteries 31 by activation of the discharge circuit 70 off (S90). In particular, the CPU calculates 61 Discharge time of the secondary batteries 31A - 31C respectively based on the charge amount differences DC1 - DC3 and the discharge current that has been set, and switches the discharge switch SW of the secondary batteries 31A - 31C corresponds only during the discharge period to perform the discharge separately. This will make the secondary batteries 31A - 31C discharge, and the charge quantities of these batteries become the charge amount of the secondary batteries 31D equalized.

3. Effects of this embodiment

Next, effects of this embodiment will be described. As described above, by adjusting the voltage of the secondary battery 31D whose voltage at the reference time T0 is lowest, as the target voltage V0, the times T1-T3 at which the voltages of the other secondary batteries 31A - 31C with voltages higher than the secondary battery 31D , the target voltage V0 have been reliably determined, since the voltages of these batteries have already reached the target voltage V0. With this, it is possible to reliably detect the time differences DT1 - DT3 concerning the times T1-T3 at which the voltages of the batteries have reached the target voltage V0 and the charge amount differences DC1 - DC3 between the plural secondary batteries 31 based on the time differences DT1 - DT3.

If a static value is taken as the target voltage, the following problems are conceivable. For example, if the target voltage is set to a static value that is relatively high (for example, 3.55V, as in FIG 5 is shown), then possibly reaches the voltage of the secondary batteries 31 , whose voltage is low (for example, the secondary voltage 31D ) the target voltage is not. Consequently, it is not possible to change the charge amount differences between the secondary battery 31D and the other secondary batteries 31 estimate. If the target voltage is at a lower static value (for example, 3.45 V, as in 5 is shown), considering the previous situation, it is difficult to estimate the charge amount differences since there is little difference between the voltages of the secondary batteries 31 gives. In contrast, according to this embodiment, the appropriate target voltage V0 is set on the basis of the voltage value measured during the constant current charge, and therefore, it is possible to calculate the charge amount differences for the plural secondary batteries 31 estimate.

<Second Embodiment>

With reference to 6 and 7 Next, a second embodiment will be described. This embodiment is different from the first embodiment in the sequence of executing the compensation control. In this case, the same components as in the first embodiment are denoted by the same reference numerals. The sequence for the execution of in 6 The compensation control shown comprises steps S110 to S200. Further, in the following description, the change with time of voltage values of the four secondary batteries becomes 31 (Reference 31A - 31D ) in a final phase of loading (see 7 ) is used as an example.

<Operation during the constant current charge>

If, as in 6 is shown, the composite battery 30 with the battery charger 11 is connected by an operator and a constant current charge of the assembled battery 30 by means of the battery charger 11 starts (S110), then draws the CPU 61 a voltage value of the secondary battery 31A whose voltage is highest in the memory 63 on (S120). Furthermore, the CPU records 61 for the secondary batteries 31B - 31D Voltages in the memory 63 on, just before the constant current charge ends (S130). Upon completion of the constant current charge of the assembled battery 30 by means of the battery charger 11 (S140) then terminates the CPU 61 the recording of the voltage value of the secondary battery 31A (S150).

<Zielspannungseinstellvorgang>

Next is the CPU 61 as the target voltage V0, voltages of the secondary batteries, respectively 31B - 31D (the secondary batteries, not the secondary battery 31A are at the reference time T0 when the constant current charge ends (see 7 ) (S160). Here is the secondary battery 31A an example of the "highest voltage energy storage device" and the "high voltage energy storage device". Further, each of the secondary batteries 31B - 31C an example of the "low voltage energy storage device" and the secondary battery 31D is an example of the "lowest voltage energy storage device" and the "low voltage energy storage device".

<Time determination process>

Next, the CPU determines 61 Time points (times T1, T4 and T5), in each case the voltage of the secondary battery 31A reaches the target voltage V0 (S170). At the in 7 Time T1 reaches the voltage of the secondary battery 31A the voltage of the secondary battery 31D at the reference time T0 (the target voltage V0) for the secondary battery 31D ). Specifically, the timing T1 (first timing) is an example of a "timing at which the voltage of the highest-voltage power storage device reaches the target voltage V0 of the lowest-voltage power storage device". Furthermore, reached at the in 7 T4 shown the voltage of the secondary battery 31A the voltage of the secondary battery 31C at the reference time T0 (the target voltage V0 for the secondary battery 31C ). Furthermore, reached at the in 7 T5 shown the voltage of the secondary battery 31A the voltage of the secondary battery 31B at the reference time T0 (the target voltage V0 for the secondary battery 31B ).

<Time difference calculation process>

Next, the CPU calculates 61 the time differences DT4 - DT6 between the time T1 and the reference time T0, the time T5 and the time T4 (S180). More specifically, in this embodiment, the time differences are calculated on the basis of the time T1. The time differences DT4 - DT6 are calculated based on the following expressions (7) to (9), respectively. Incidentally, the time T5 and the time T4 are an example of a "time other than the time T1 detected in the time-determining process". DT4 = T0 - T1 (7) DT5 = T5 - T1 (8) DT6 = T4 - T1 (9)

<Ladungsmengendifferenzabschätzvorgang>

Next, the CPU appreciates 61 the charge amount differences between the secondary battery 31D and the respective secondary batteries 31A - 31C based on the time differences DT4 - DT6 and the charging current from (S190). In particular, when the charge amount difference between the secondary battery 31D and the secondary battery 31A is equal to DT4, the charge amount difference between the secondary battery 31D and the secondary battery 31B is equal to DC5 and if the charge quantity difference between the secondary battery 31D and the secondary battery 31C is equal to DC6, the charge amount differences DC4 - DC6 are calculated according to the following expressions ( 10 ) to (12). Charge quantity difference DC4 = time difference DT4 · charge current ZI (10) Charge quantity difference DC5 = time difference DT5 · charge current ZI (11) Charge quantity difference DC6 = time difference DT6 · charge current ZI (12)

<Settlement process>

Next, the CPU is the same 61 the charge quantities of the secondary batteries 31 by activation of the discharge circuit 70 off (S200). In particular, the CPU calculates 61 the discharge time of the secondary batteries 31A - 31C according to the charge amount differences DC4 - DC6 and the discharge current that has been set, and switches the discharge switch SW of the secondary batteries 31A - 31C corresponds only during the discharge period to perform a separate discharge. This will make the secondary batteries 31A - 31C discharge and the charge quantities of these batteries become the charge amount of the secondary battery 31D equalized.

Next, effects of this embodiment will be described. In this embodiment, the target voltage V0 becomes for each of the secondary batteries 31B - 31C set, and the times at which the voltage of the secondary battery 31A each reaches the target voltage are calculated. Thereby, it is possible to estimate the charge amount differences on the basis of the time differences at the calculated times.

Further, in order to estimate the charge amount differences on the basis of the time differences, it is necessary to determine the times at which the voltages of the secondary batteries 31 reach the target voltage V4, and therefore determine the temporal change in the tensions of the secondary bacteria 31 record. According to the first embodiment described above, it is necessary to determine the times at which the voltages of the secondary batteries 31A . 31B and 31C reach the target voltage V0, and determine the temporal change of the voltages of the secondary batteries 31A . 31B and 31C record. On the other hand, according to this embodiment, it is necessary to merely change the voltage of the secondary battery over time 31A to determine whose voltage is highest, and therefore it is possible to reduce the amount of data to be recorded.

<Third Embodiment>

Next, a third embodiment in which the technique disclosed herein is applied to a vehicle such as an automobile 110 , is applied with reference to 8th to 11 described. In this case, the same components as in the previously described embodiments are denoted by the same reference numerals. As in 8th is shown, the automobile 110 a vehicle consumer 112 , a battery module 130 (Energy storage module), with the vehicle consumers 112 is connected, an on-board electronic control 113 (ECU), which is the function of the vehicle user 112 controls, and a power generator 111 for a vehicle (see 9 ). This includes examples of the vehicle user 112 a starter motor for starting an internal combustion engine, a headlight, an interior light, an audio device, a clock and a safety device with a.

As further in 9 is shown is the vehicle consumer 112 with the battery module 130 and the power generator 110 connected and is formed by supplying power from the battery module 130 and the power generator 111 to work. Further, the power generator 111 designed to generate power by driving from the internal combustion engine of the automobile 110 is set in rotation. Further, when the magnitude of the power generation by the power generator 111 is greater than the amount of power consumption by the vehicle user 112 For example, while the vehicle is running, power is taken from the power generator 111 the vehicle consumer 112 fed and the battery module 130 is charged by the excess power. In particular, the power generator serves 111 as the battery charger for charging the battery module 130 ,

The vehicle-side electronic control 113 is with the vehicle consumer 112 , the power generator 111 , the battery module 130 and the like are connected via a communication line and controls the vehicle user 112 on the basis of a condition of the automobile 110 , a state of the battery module 130 and the same.

As in 9 is shown, the battery module 130 According to this embodiment, the plurality of secondary batteries 31 , the BM 50 and a battery case 131 for holding the several secondary batteries 31 and the BM 50 on. Furthermore, the controller has 60 According to this embodiment, a communication unit 165 which is capable of using the on-vehicle electronic control 113 to carry out a communication.

The battery case 131 is for example made of synthetic resin and has a block shape, as in 10 is shown. Furthermore, as in 11 is shown, the battery case 131 a housing main body 132 with an opening on an upper side, a positioning element 133 for positioning the multiple secondary batteries 31 , an inner cover 134 on the top of the case main body 132 attached, and a top cover 135 on top of the inner cover 134 is appropriate. It is in 10 and 11 in a state in which the battery case 131 is arranged without inclination with respect to a mounting surface, a vertical direction of the battery case 131 as a Y-axis direction, a direction along a length of the battery case 131 is used as an X-axis direction and a depth direction of the battery case 131 corresponds to a Z-axis direction.

As in 11 are shown in the housing main body 132 several cell compartments 132A corresponding to the multiple secondary batteries 31 contained along the X-axis direction. On an upper surface of the positioning element 133 are several busbars 133A arranged. By providing the positioning element 133 over the several secondary batteries 31 within the housing main body 132 become the multiple secondary batteries 31 through the multiple busbars 133A positioned and connected in series.

As in 11 is shown, the inner cover 134 in it a circuit board 136 contain. The circuit board 136 is trained, the controller 60 and the voltage detection circuit 80 in the BM 50 this being a non-limiting example. Here are the discharge circuit 70 , the current sensor 40 and the temperature sensor 95 in 11 not shown.

As in 10 is shown is an upper wall 138 of the battery case 131 provided essentially in rectangular shape and is covered by the inner cover 134 and the top cover 135 educated. The upper wall 138 is provided in a stepped form, with an area passing through the inner cover 134 is formed lower than an area through the top cover 135 is formed. The lower area of the upper wall 138 (the inner cover 134 ) has a pair of terminal sections 137 to which wiring harness terminals (not shown) are connected and which are arranged at both ends of the X-axis direction. The connection sections 137 are made of metal, such as a lead alloy, and a lower part of each terminal portion is in the inner cover 134 embedded. It is one of the two connection sections 137 a connection section on the positive side 137P and the other is a connection section on the negative side 137n ,

As described above, in this embodiment, the BMs 50 and the multiple secondary batteries 31 in the battery case 131 contain. Thereby, it is possible to follow the sequence for executing the equalization control described in the first and second embodiments on the battery module 130 to do that in the automobile 110 is installed.

Other Embodiments

• (1) In den vorhergehenden Ausführungsformen wird eine Lithiumionensekundärbatterie unter Anwendung eines positiven aktiven Materials auf Basis von Eisenphosphat als ein Beispiel der Energiespeichereinrichtung verwendet. Jedoch ist die hierin offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt, und es kann eine andere Sekundärbatterie als die Lithiumionensekundärbatterie oder es kann eine elektrochemische Zelle, etwa ein Kondensator in Verbindung mit elektrochemischen Phänomenen, als die Energiespeichereinrichtung verwendet werden.
• (2) In den vorhergehenden Ausführungsformen wird die Steuerung 60 mit der CPU 61 als Beispiel verwendet, jedoch ist die hierin offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt. Die Steuerung kann einen Aufbau haben, in welchem mehrere CPUs vorgesehen sind oder die Steuerung kann eine Hardwareschaltung, etwa eine ASIC (anwendungsspezifische integrierte Schaltung), oder ein Mikrocomputer, ein FPGA, eine MPU oder eine Kombination davon sein. Anders ausgedrückt, die Steuerung kann einen beliebigen Aufbau haben, der in der Lage ist, die Abfolge zur Ausführung der Ausgleichssteuerung auszuführen, die in den vorhergehenden Ausführungsformen beschrieben ist, wobei Software oder eine Hardwareschaltung verwendet werden.
• (3) In den vorhergehenden Ausführungsformen wird der Aufbau, in welchem die zusammengesetzte Batterie 30 die vier Sekundärbatterien 31 enthält, als ein Beispiel verwendet, jedoch ist die hierin offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt. Sofern mindestens zwei Sekundärbatterien 31 vorgesehen sind, kann die Anzahl in geeigneter Weise geändert werden.
• (4) In den vorhergehenden Ausführungsformen wird der Fall, in welchem die Konstantstromladung an der zusammengesetzten Batterie 30 vorgenommen wird und anschließend der Ausgleichsvorgang auf der Grundlage des Ergebnisses der Konstantstromladung ausgeführt wird, als Beispiel verwendet, jedoch ist die offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt. Beispielsweise ist auch der Fall vorgesehen, in welchem Konstanststrom-Konstantspannungsladung an der zusammengesetzten Batterie 30 ausgeführt wird und anschließend der Ausgleichsvorgang auf der Grundlage eines Ergebnisses der Konstantstrom-Konstantspannungsladung ausgeführt wird. Wenn dabei die Konstantstrom-Konstantspannungsladung ausgeführt wird, ist es vorstellbar, dass Beträge (hoch und niedrig) der Spannungen der Sekundärbatterien 31, wenn die Konstantstromladung endet, und Beträge (hoch und niedrig) der Spannungen der Sekundärbatterien 31 während der Konstantspannungsladung einander entgegengesetzt sind auf Grund der individuellen Schwankung des Innenwiderstands, die jeweils für die Sekundärbatterien 31 gegeben sind. In einem derartigen Falle können die Ladungsmengendifferenzen, die auf der Grundlage der Spannungen der Sekundärbatterien 31 abgeschätzt wurden, wenn die Konstantstromladung endet, korrigiert werden, und der Ausgleichsvorgang kann auf der Grundlage des korrigierten Wertes ausgeführt werden.
• (5) In den vorhergehenden Ausführungsformen ist das Verfahren zum Ausgleichen der Ladungsmengen durch Entladung einer der Sekundärbatterien 31, deren Ladungsmenge relativ groß ist, als ein Beispiel verwendet, jedoch ist die hierin offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt. Beispielsweise können die Ladungsmengen dadurch ausgeglichen werden, dass eine der Sekundärbatterien 31, deren Ladungsmenge relativ klein ist, aus einer weiteren Sekundärbatterie 31 geladen wird, deren Ladungsmenge relativ groß ist. Jedoch führt in einem Falle, in welchem das Laden nur zwischen den mehreren Sekundärbatterien 31 und ohne Aufnahme von Leistung aus einer externen Leistungsquelle ausgeführt wird, das Laden einer der Sekundärbatterien 31 zu einer Verringerung der Ladungsmengen der anderen Sekundärbatterien 31, und daher wird der Vorgang des Ausgleichens erschwert. Im Gegensatz dazu ist das Ausführen des Ausgleichs durch Entladung vorteilhaft, da es möglich ist, einen Ausgleich aller Sekundärbatterien zu ermöglichen, indem andere Sekundärbatterien auf der Grundlage beispielsweise einer Sekundärbatterie entladen werden, deren Ladungsmenge am Kleinsten ist.
• (6) In den vorhergehenden Ausführungsformen wird der Fall, in welchem die Ladungsmengendifferenzen zu den anderen Sekundärbatterien 31 auf der Grundlage der Sekundärbatterie 31D abgeschätzt wird, deren Spannung am niedrigsten ist, als ein Beispiel verwendet, jedoch ist die hierin offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt.
• (7) In den vorhergehenden Ausführungsformen wird der Zeitpunkt, an welchem die Konstantstromladung endet, als der Referenzzeitpunkt T0 festgelegt, jedoch ist die hierin offenbarte Technik nicht auf das zuvor beschriebene Beispiel beschränkt. Obwohl der Referenzzeitpunkt T0 als geeigneter Zeitpunkt eingestellt bzw. festgelegt werden kann, solange dieser ein Zeitpunkt während der Konstantstromladung ist, ist es bevorzugt, einen Zeitpunkt einzustellen bzw. festzulegen, an welchem Spannungsdifferenzen zwischen den Sekundärbatterien 31 deutlich sind, um die Genauigkeit beim Abschätzen der Ladungsmengendifferenzen zu verbessern. Insbesondere ist es bevorzugt, dass ein Zeitpunkt in dem Zeitraum, in welchem die mehreren Sekundärbatterien 31 in einem Gebiet mit großer Änderung liegen (beispielsweise die Endphase des Ladens) als der Referenzzeitpunkt T0 festgelegt wird, da dies zu deutlichen Spannungsdifferenzen zwischen den Sekundärbatterien 31 führt.

Aspects of the technique disclosed herein are not limited to the embodiments in the foregoing description with reference to the drawings, and various aspects may be included, which are described below.

• (1) In the foregoing embodiments, a lithium-ion secondary battery using a ferrous phosphate-based positive active material is used as an example of the energy storage device. However, the technique disclosed herein is not limited to the above-described example, and may be a secondary battery other than the lithium-ion secondary battery, or an electrochemical cell, such as a capacitor in conjunction with electrochemical phenomena, may be used as the energy storage device.
• (2) In the foregoing embodiments, the control becomes 60 with the CPU 61 as an example, however, the technique disclosed herein is not limited to the example described above. The controller may have a structure in which a plurality of CPUs are provided, or the controller may be a hardware circuit such as an ASIC (Application Specific Integrated Circuit), or a microcomputer, an FPGA, an MPU, or a combination thereof. In other words, the controller may have any structure capable of executing the sequence for executing the equalization control incorporated in the In the foregoing embodiments, software or a hardware circuit is used.
• (3) In the foregoing embodiments, the structure in which the assembled battery 30 the four secondary batteries 31 contains, as an example, but the technique disclosed herein is not limited to the example described above. If at least two secondary batteries 31 are provided, the number can be changed as appropriate.
• (4) In the foregoing embodiments, the case in which the constant current charge is applied to the assembled battery becomes 30 is performed and then the equalizing operation is carried out on the basis of the result of the constant current charge as an example, however, the disclosed technique is not limited to the above-described example. For example, the case is also provided in which Konstanststrom constant voltage charge to the assembled battery 30 is performed, and then the equalizing operation is performed on the basis of a result of the constant-current constant-voltage charge. When doing the constant-current constant-voltage charging, it is conceivable that amounts (high and low) of the voltages of the secondary batteries 31 when the constant current charge ends and amounts (high and low) of the voltages of the secondary batteries 31 during the constant voltage charging are opposite to each other due to the individual variation of the internal resistance, respectively, for the secondary batteries 31 given are. In such a case, the charge amount differences based on the voltages of the secondary batteries 31 are estimated to be corrected when the constant current charge ends, and the equalizing operation may be performed on the basis of the corrected value.
• (5) In the foregoing embodiments, the method of compensating the amounts of charge by discharging one of the secondary batteries 31 , whose charge amount is relatively large, used as an example, however, the technique disclosed herein is not limited to the example described above. For example, the charge quantities can be compensated by one of the secondary batteries 31 whose charge quantity is relatively small, from another secondary battery 31 is charged, the amount of charge is relatively large. However, in a case where the charging occurs only between the plural secondary batteries 31 and without taking power from an external power source, charging one of the secondary batteries 31 to a reduction in the charge amounts of the other secondary batteries 31 , and therefore the process of balancing is made more difficult. In contrast, performing the equalization by discharge is advantageous because it is possible to enable equalization of all the secondary batteries by discharging other secondary batteries based on, for example, a secondary battery whose charge amount is smallest.
• (6) In the foregoing embodiments, the case in which the charge amount differences become the other secondary batteries 31 based on the secondary battery 31D is estimated to be lowest in voltage as an example, however, the technique disclosed herein is not limited to the example described above.
• (7) In the foregoing embodiments, the timing at which the constant current charge ends is set as the reference timing T0, but the technique disclosed herein is not limited to the example described above. Although the reference timing T0 may be set as an appropriate timing as long as it is a timing during the constant current charge, it is preferable to set a timing at which voltage differences between the secondary batteries 31 are clear to improve the accuracy in estimating the charge quantity differences. In particular, it is preferable that a timing in the period in which the plurality of secondary batteries 31 in an area of large change (for example, the final stage of charging) is set as the reference time T0, since this results in significant voltage differences between the secondary batteries 31 leads.

• (8) In der dritten Ausführungsform wird der Fall, in welchem das Batteriemodul (Energiespeichermodul) in einem Fahrzeug montiert ist und das Batteriemodul mit Fahrzeugverbrauchern einschließlich eines Anlassermotors, eines Scheinwerfers, einer Innenbeleuchtung, einer Audio-Einrichtung, einer Uhr und einer Sicherheitseinrichtung verbunden ist, als ein Beispiel verwendet. Alternativ kann die vorliegende Erfindung angewendet werden, um einen Zustand einer Energiespeichereinrichtung abzuschätzen, die in einem zweirädrigen Fahrzeug, einem Schienenfahrzeug, in einer unterbrechungsfreien Energieversorgung (UPS), einer regenerativen leistungsaufnehmenden Vorrichtung, einer Energiespeichervorrichtung für die Leistungserzeugung durch natürliche Energien, oder dergleichen, vorgesehen ist. Ein Teil oder alle Funktionen der Zustandsabschätzeinrichtung können an einem entfernten Ort angeordnet sein, und die Zustandsabschätzeinrichtung kann mit einer Energiespeichereinrichtung oder einem Energiespeichermodul über ein Netzwerk verbunden sein. Ferner kann die Zustandsabschätzeinrichtung in einem Server-Rechner in einem Netzwerk implementiert sein.

It should be noted that there is a turning point at which a rate of change of the OCV of the secondary batteries 31 is above a predetermined value between the low-change area and the high-change area. Therefore, when the reference timing T0 is set in a time range in which the voltage of one of the secondary batteries 31 whose voltage is lowest (the secondary battery 31D ) exceeds a voltage corresponding to the inflection point, the voltage differences between the secondary batteries become 31 clearly, as the multiple secondary batteries 31 in the area of great change, and it is possible to more reliably estimate the charge quantity differences.

• (8) In the third embodiment, the case in which the battery module (energy storage module) is mounted in a vehicle and the battery module with vehicle consumers including a starter motor, a headlamp, an interior lighting, an audio device, a clock and a security device is used as an example. Alternatively, the present invention may be applied to estimate a state of an energy storage device provided in a two-wheeled vehicle, a rail vehicle, an uninterruptible power supply (UPS), a regenerative power receiving device, a power storage device for natural power generation, or the like is. A part or all of the functions of the state estimator may be located at a remote location, and the state estimator may be connected to an energy storage device or an energy storage module via a network. Furthermore, the state estimator can be implemented in a server computer in a network.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2011-41452 A [0002, 0002, 0003]

Claims (8)

A state estimator that estimates a state of a plurality of energy storage devices, the state estimation device comprising: a voltage detection unit configured to detect respective voltages of the energy storage device; and an estimation unit configured to estimate a charge quantity difference between at least two of the energy storage devices, wherein, at a reference time T0 during a constant-current charging, the plurality of energy storage devices in a case where one of the two energy storage devices is a low-voltage energy storage device whose voltage is relatively low, and the other of the two energy storage devices is a high-voltage energy storage device whose voltage is relatively high is high, the estimation unit executes: a target voltage setting operation for setting, as a target voltage V0, a voltage of the low-voltage energy storage device detected by the voltage detection unit at the reference time T0; a time determination process for detecting a timing at which a voltage of the high-voltage energy storage device reaches the target voltage V0; and a charge amount difference estimation process for estimating the charge amount difference between the at least two energy storage devices based on the reference time T0, the time point determined in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge. The state estimating device according to claim 1, wherein the plurality of energy storage devices comprises three or more energy storage devices, and if one of the plurality of energy storage devices is a lowest voltage energy storage device whose voltage is lowest at the reference time T0, the estimating unit: in the target voltage setting operation, setting a voltage of the lowest-voltage energy storage device as the target voltage V0; determining, in the time-determining process, times at which voltages of the plurality of energy storage devices that are not the lowest-voltage energy storage device reach the target voltage V0; and in the charge amount difference estimation process, estimates the charge amount differences between the plurality of energy storage devices based on the reference time T0, the times detected in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge. The condition estimating device according to claim 2, where the estimation unit: calculate a time difference calculation process for calculating time differences between the reference time T0 and the times determined in the time determination process; and in the charge amount difference estimation process, the charge amount differences between the lowest voltage energy storage device estimates the energy storage devices that are not the lowest voltage energy storage device based on the time differences calculated in the time difference calculation process. The state estimating device according to claim 1, wherein the plurality of energy storage devices comprises three or more energy storage devices, and in a case where one of the plurality of energy storage devices is a highest voltage storage device whose voltage is highest at the reference time T0, the estimating unit: in the target voltage setting operation, setting voltages of the plurality of energy storage devices other than the highest voltage energy storage device as target voltages V0; in the time determination process, determine timings at which a voltage of the highest voltage power storage device reaches the target voltages V0 set in the target voltage setting operation; and in the charge amount difference estimation process, estimates the charge amount differences between the plurality of energy storage devices based on the reference time T0, the times detected in the time determination process, and a current flowing through the plurality of energy storage devices during the constant current charge. The state estimating device according to claim 4, wherein in a case where one of the plurality of energy storage devices is a lowest voltage energy storage device whose voltage is lowest at the referencing timing T0, the estimation unit: executes a time difference calculation process for calculating a time difference between the time point T1 and the reference time point T0 and Time differences between the time T1 and the times other than the time T1 detected in the time-determining process, the time T1 being a time at which a voltage of the highest-voltage power storage means reaches the target voltage V0 of the lowest-voltage power storage means; and in the charge amount difference estimation process, estimating the charge amount differences between the lowest voltage energy storage device and the energy storage devices from the plurality of energy storage devices that are not the lowest voltage energy storage device based on the time differences calculated in the time difference calculation process. An energy storage module with: a plurality of energy storage devices; and The condition estimating device according to any one of claims 1 to 5. A vehicle with: the energy storage module according to claim 6; and a vehicle consumer, the power is supplied from the energy storage module. A state estimation method for estimating a state of multiple energy storage devices, the method comprising: Setting, at a reference instant T0, during a constant current charge to a plurality of energy storage devices, a voltage of a low voltage energy storage device as a target voltage V0, wherein one of at least two of the plurality of energy storage devices is the low voltage energy storage device having a relatively low voltage and the other one of the two energy storage devices is a high voltage energy storage device whose voltage is relatively high; Determining a time at which a voltage of the high-voltage energy storage device reaches the target voltage V0; and Estimating a charge amount difference between the at least two energy storage devices based on the reference time T0, the time detected in the time determination, and a current flowing through the plurality of energy storage devices during the constant current charge.

Images